JP2003252984A - beta-POLYPEPTIDE DERIVATIVE, ITS MANUFACTURING METHOD AND ITS MOLDED PRODUCT - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroconductor having excellent molding properties. <P>SOLUTION: The β-polypeptide derivative comprises a β-polypeptide as the main chain and has a substituent group bearing an electroconductive group as a side chain in the main chain with the substitution degree of substantially 100%. As the β-polypeptide derivative forms a 4/1-helix structure where four residual groups constitute one revolution and side chains bearing the electroconductive groups stand in the same plane, charge transfer between side chains progresses smoothly to permit exhibition of excellent electroconductivity. Moreover, the β-polypeptide derivative does not contain a conjugated structure in the main chain unlike a polyacetylene and the like, and therefore it permits easy molding processing. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a β-polypeptide derivative, a process for producing the same, and a molded product thereof.

[0002]

2. Description of the Related Art In recent years, organic conductors such as polyacetylene have been studied as new conductors used for secondary batteries, LEDs, electronic circuit elements, electromagnetic wave shields and the like.

[0003]

However, since these organic conductors are insoluble and infusible and difficult to handle, they cannot be said to be sufficient in terms of moldability and the like, and they are not practical.

The present invention has been made in order to solve the above problems, and an object thereof is to provide an organic conductor having high practicality.

[0005]

[Means for Solving the Problems] The inventors of the present invention have conducted extensive studies to solve such problems. As a result, a side chain type polymer having a conductive group is considered to be effective, and β-polypeptide as a main chain, a substituent having a conductive group on the main chain as a side chain, and the degree of substitution is substantially Β- having at 100%
The inventors have found that a polypeptide derivative can be an organic conductor having a particularly high practicality, and have completed the present invention.

Here, the relationship between the structure and conductivity of the β-polypeptide derivative of the present invention will be described in comparison with α-polypeptide having an α-helix structure.

The α-helix structure, which is the secondary structure of α-polypeptide, has a side chain radially protruding toward the outside of a rigid rod-shaped molecule when viewed from the axial direction of the helix as shown in FIG. It maintains the characteristic space layout. This α
In the -helix structure, the side chain is not aligned on the same plane, although the side chain spatial arrangement is maintained to some extent because it makes 5 turns at 18 residues, or 1 turn at 3.6 residues. Therefore, it is considered that in the α-helix structure, even if a conductive group is introduced into the side chain, the charge transfer between the side chains is not so smooth.

FIG. 2 shows the structure of poly (α-N-pyrenemethyl L-aspartamide) (PPMAA) as an example of the β-polypeptide derivative of the present invention. Note that FIG.
FIG. 2A is a view from a direction intersecting the axis of the helix, and FIG. 2B is a view seen from the axial direction of the helix. As shown in FIG. 2, β-polypeptide derivatives are
It forms a 4 / 1-helix structure that rotates once with residues,
It is considered that the side chains are arranged on the same plane. The β-polypeptide derivative of the present invention has a substituent having a conductive group as a side chain and a degree of substitution of substantially 100%. Therefore, in the β-polypeptide derivative of the present invention, since the substituents having a conductive group are regularly arranged on the same plane, charge transfer between side chains is very smoothly performed, and excellent conductivity is exhibited. It is considered to be a thing.

The β-polypeptide derivative of the present invention exhibits conductivity due to charge transfer between side chains, and its basic structure is completely different from that of polyacetylene having a conjugated structure in its main chain. It is a thing.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The β-polypeptide derivative of the present invention has the general formula

[Chemical 3] It has substantially 100% of the structural unit represented by the formula (wherein R represents a substituent having a conductive group), and the main chain is a β-polypeptide. Examples of the main chain include polymers of aspartic acid.

The molecular weight of the β-polypeptide derivative of the present invention is not particularly limited. The viscosity average molecular weight is preferably 100,000 or more, and particularly preferably 500,000 to 1,000,000.

The β-polypeptide derivative of the present invention has a conductive group in the side chain, and the conductive group is not particularly limited as long as it has conductivity, and examples thereof include a pyrenyl group and a naphthyl group. , Condensed polycyclic hydrocarbon groups such as anthranyl group, thiophene group, phenyl group, and pyrrole group. These groups are substituted with an alkyl group having 1 to 6 carbon atoms, an alkoxy group, a halogen group, or a halogen-substituted alkyl group. It may have been done. Of these, a pyrenyl group or a thiophene group is preferable. This is because the β-polypeptide introduced with a pyrenyl group or a thiophene group has particularly excellent conductivity.

Examples of the β-polypeptide derivative of the present invention include those represented by the general formula:

[Chemical 4] (In the formula, R represents R = CONHR ₁ , R = COOR ₁ , or R = (CH ₂ ) _n- R _1. However, R ₁ represents a substituent having a conductive group.). And β-polypeptide derivatives having substantially 100% of the constituent units.

In the present invention, preferred β-polypeptide derivatives include, for example, compounds of the general formula

[Chemical 5] A poly (β-aspartamide) having substantially 100% of a structural unit represented by the formula (wherein R represents a conductive group), and a general formula

[Chemical 6] Poly (β-aspartate) having substantially 100% of the structural unit represented by the formula (R represents a conductive group) is exemplified.

Next, a method for producing the β-polypeptide derivative of the present invention will be described. The method for producing the β-polypeptide derivative is not particularly limited, and a known production method can be used.

[Chemical 7] A production method is preferred in which the β-polypeptide derivative having substantially 100% of the structural unit represented by is reacted with an amine or alcohol having a conductive group to substitute the benzyl group of the side chain with the conductive group. Regarding this production method, poly (α-N-pyrenemethyl L-aspartamide) (PP
The case of MAA) will be described in detail with reference to Scheme 1.

[0016]

[Chemical 8]

In this production method, β-polypeptide 4 having a benzyl group on its side chain is used. This β-polypeptide 4 was prepared by dissolving β-lactam 3 having a benzyl group on its side chain in a solvent, and then dissolving it. It is prepared by adding an initiator and polymerizing.

The solvent is not particularly limited as long as it can dissolve β-lactam, and for example, anhydrous methylene chloride (DCM), chloroform (CF), dimethylsulfoxide (DMSO), dimethylformamide (DMF) can be used. In particular, DCM and CF are preferable because they have high polymerizability.

The reaction temperature varies depending on the type of β-lactam, the type of solvent, the reaction apparatus and the like and is not particularly limited, but is preferably -10 to 60 ° C, more preferably 0 to 10 ° C. . When the temperature is lower than -10 ° C, the reactivity is lowered, and when the temperature is higher than 60 ° C, the produced β-polypeptide may be decomposed or a side reaction such as succinimide may occur.

The initiator is not particularly limited, and known initiators can be used. For example, as an initiator
Sodium pyrrolidone (NaPy), potassium t-butoxide
(t-BuOK) and potassium pyrrolidone (KPy). The amount of the initiator is 1/1000 to 1/5 times mol with respect to β-lactam.
And preferably 1/100 to 1/10 times mol.

The reaction time varies depending on the type of β-lactam, the type of solvent, the reaction apparatus and the like and is not particularly limited. For example, β-lactam may be (S) -4-benzyloxycarbonyl-2-azetidinone. ((S) -4-Benzyloxycarbon
yl-2-Azetidinone), the reaction temperature is about 0.
It is about 1 hour at ℃. This is because even if the reaction is carried out for a too long time, the polymerization is instantaneously terminated, and a long-time reaction is not so meaningful.

Next, the side chain benzyl group of the β-polypeptide is replaced with an amine or alcohol having a conductive group. In order to displace the side chain, β-polypeptide is dissolved in a solvent, and an amine having a conductive group is added to this solution.

The solvent is not particularly limited as long as it can dissolve β-polypeptide, and examples thereof include m-cresol, DMF, DMS.
O and CF can be used.

The reaction temperature varies depending on the type of β-polypeptide, the type of solvent, the type of amine or alcohol having a conductive group, the reaction apparatus, etc. and is not particularly limited, but preferably 50 to 120 ° C. , And more preferably,
It is 50 to 70 ° C. This is because if the temperature is lower than 50 ° C, the reactivity is lowered, and if the temperature is higher than 120 ° C, the produced β-polypeptide may be decomposed.

The reaction time varies depending on the type of β-polypeptide, the type of solvent, the reaction apparatus, etc. and is not particularly limited. For example, β-polypeptide may be poly (α-
When benzyl L-aspartate) (PBLA) is used, the reaction temperature is about 58 ° C. for 7 days.

In the above-mentioned production method, the side chain is substituted after the polymerization, but the present invention is not limited to this. First, β-lactam having a conductive group is synthesized, and then this β-lactam is polymerized. Of course, it may be a manufacturing method. Alternatively, a method by a transesterification reaction using p-toluenesulfonic acid, or β-polypeptide such as PBLA obtained by polymerization is trimethylsilane iodide, a side chain is converted to a carboxylic acid, and then a conductive group is introduced. It can also be manufactured by the method.

Next, a molded article containing the β-polypeptide derivative will be described. The size and shape of the molded body is
There are no particular restrictions, depending on the application for which the molded product is used, and it may be, for example, a film or plate.

The manufacturing method is not particularly limited, and β
A solution casting method of casting a solution containing a polypeptide derivative to form a film, an injection molding method, an inflation molding method,
The T-die molding method, calender roll molding method, extrusion molding method and the like can be widely adopted. The β-polypeptide derivative of the present invention, unlike polyacetylene and the like, does not contain a conjugated structure in its main chain, and therefore can be easily molded.

The ratio (weight ratio) of the β-polypeptide derivative to the other composition in the molded article is not particularly limited, but preferably the ratio of the β-polypeptide derivative to the other composition is 50:50 to 100: 0 (weight ratio)
And more preferably 70:30 to 100: 0.
(Weight ratio), and particularly preferably 90:10 to 10
It is 0: 0. Β- than mixing ratio 50:50 (weight ratio)
This is because if the amount of the polypeptide derivative is small, the conductivity is slightly lowered.

The composition other than the β-polypeptide derivative is not particularly limited, and examples thereof include known resins, pigments, various stabilizers, ultraviolet absorbers and fillers.

When the molded product is in the form of a film, it is preferably stretched using a known stretching machine such as a roll stretching machine or a tenter stretching machine. By stretching in this way, the orientation of β-polypeptide is improved,
This is because the side chains having a conductive group are more regularly arranged on the same plane, so that the conductivity is remarkably improved.

In the stretching treatment, the stretching ratio is 1.
5-2.5 times is preferable. If it is less than 1.5 times, a non-stretched portion remains and uneven stretching occurs, so that a uniform molded product may not be obtained in some cases, while if it exceeds 2.5 times, it may break, which is not so preferable. Here, the stretching ratio means a value obtained by dividing the dimension after the stretching treatment by the dimension before the stretching treatment.

[0033]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto. <Synthesis of β-lactam> Schemes 2 and 3 show the synthesis schemes of β-lactam.

[0034]

[Chemical 9]

[0035]

[Chemical 10]

First, dibenzyl ester was synthesized from L-aspartic acid (L-Asp) by an azeotropic method. Azeotropic method
A Dean-Stark apparatus was used. L-aspartic acid (50.0g,
0.376mol) and p-toluenesulfonic acid (p-Tos) (85.8g, 0.4
51 mol) and benzyl alcohol (BzlOH) (150 ml, 1.446 mol)
And and put in a three-necked flask, the solvent benzene (Bz) (300 ml)
Was used and reacted at 110 ° C. for 2 hours with stirring. When the generation of water is completed, 100 ml of benzene is added to the system,
The mixture was stirred and reacted at the same temperature for 5 hours. After the reaction, the mixture was allowed to cool slowly at room temperature and the formation of crystals was promoted while adding ether. The produced p-toluenesulfonate crystal of L-dibenzyl aspartate (L-Asp (OBzl) OBzl · Tos) was collected by filtration,
The crystals were washed with ethanol and ether, collected, and recrystallized with methanol for purification.

Next, the obtained p- of L-Asp (OBzl) OBzl · Tos was obtained.
The toluene sulfonate was removed by alkali treatment.
Specifically, L-Asp (OBzl) OBzlTos (50.0 g) was dissolved in methylene chloride, desalted with a saturated aqueous sodium hydrogen carbonate solution (NaHCO ₃ aq) using a separating funnel, and then purified to give an oil. H-Asp (OBzl) OBzl was obtained.

Oily H-Asp (OBzl) OBzl (0.098mo
l) was dissolved in 200 ml of benzene, 2 times mol of triethylamine (TEA) (27.3 ml) was added, and the reaction system was sufficiently cooled with ice under a nitrogen stream while chlorotrimethylsilane diluted with Bz.
(CTMS) was slowly added dropwise. As the reaction proceeds, triethylamine hydrochloride (TEA.HCl) is produced in the system, so after stirring for 4 hours, TEA.HCl was collected by filtration. After concentration under reduced pressure, it was diluted again with ether, and 1.2 times mol of t-butylmagnesium chloride (t-BuMgCl) was slowly added dropwise while maintaining the system at -20 ° C in a dry ice / methanol bath. After reacting at the same temperature for 1 hour, the temperature was returned to room temperature and the reaction was carried out with stirring overnight.

Then, ammonium chloride (NH ₄
A 2N aqueous hydrochloric acid solution saturated with Cl) was slowly added, and the mixture was stirred with ice cooling for 1 hour. After the precipitate was collected by filtration, only the ether layer was collected and washed with distilled water. After drying over anhydrous magnesium sulfate and concentrating under reduced pressure, cold ether was added to precipitate (S)-
4-benzyloxycarbonyl-2-azetidinone ((S) -4-B
enzyloxycarbonyl-2-Azetidinone) was collected. The former precipitate and the latter precipitate were recrystallized from methanol for purification (yield 50%). A melting point meter (Yanamoto Yana
When the melting point was measured using (co MP type), the melting point was 135.
It was ~ 138 ° C.

<Synthesis of Initiator Sodium Pyrrolidone (NaPy)> Scheme 4 shows a synthetic scheme of sodium pyrrolidone (NaPy) as an initiator.

[0041]

[Chemical 11] Sodium hydride (NaH) (1.0 g, 0.0417 mol) was suspended in 100 ml of anhydrous toluene (TOL), and 2-pyrrolidone (2
-Py) (3.54 ml, 0.0417 mol) was added. One hour after the generation of hydrogen stopped from the reaction system, solid NaPy was filtered and collected (yield 96%).

<Polymerization of β-lactam> Scheme 5 shows a synthetic scheme of poly (α-benzyl L-aspartate) (PBLA).

[0043]

[Chemical 12]

Crystals of β-lactam (3 g, 0.0146 mol) were ground and dissolved in anhydrous methylene chloride (DCM) (40 ml). Stirring while cooling with ice, dissolved in DCM beforehand 1/50 times mol
NaPy was added. After reacting for 1 hour, trifluoroacetic acid (T
FA) was used to dissolve the gel product and reprecipitated in methanol to give poly (α-benzyl L-aspartate) (PBLA).
Was collected by filtration (yield 97%).

<Synthesis of poly (α-N-pyrenemethyl L-aspartamide) (PPMAA)> Scheme 6 shows a synthetic scheme of poly (α-N-pyrenemethyl L-aspartamide) (PPMAA).

[0046]

[Chemical 13]

Poly (α-benzyl L-aspartate)
(PBLA) (2.21 mmol) was dissolved in m-cresol, 1-pyrenemethylamine (3.31 mmol) was added, and the mixture was allowed to stand at 58 ° C for 7 days. The reaction product was precipitated with methanol, washed, and vacuum dried to obtain ocher-colored poly (α-N-pyrenemethyl L-aspartamide) (PPMAA) (yield 90%).

<Preparation of cast film of poly (α-N-pyrenemethyl L-aspartamide) (PPMAA)> PPM
AA33 (5.2 mg) was dissolved in N, N-dimethylformamide (DMF) (2.7 ml) and cast on a Teflon (registered trademark) petri dish to obtain a cast film having a thickness of 346.2 μm.

<Iodine Doping> The produced cast film was doped with iodine, which is an electron-accepting dopant, by a vapor method. In the atmosphere, iodine was vaporized in a thermostatic chamber at 60 ° C., and in the presence of the iodine, the cast film was forcedly permeated.

<Measurement>< ¹ H-NMR measurement> ¹ HN at each synthesis step for confirmation of synthetic substance
MR spectrum measurement was performed. A Fourier transform nuclear magnetic resonance apparatus (JEOL JNM-GX400) was used for the measurement. Deuterated chloroform (CDCl ₃ ), deuterated dimethyl sulfoxide (DMSO-d6), or deuterated water (D ₂ O) was used as the measurement solvent, and tetramethylsilane (TMS) was used as the reference substance, and the sample concentration The measurement was performed at 3 wt%. The total number of times is 16 to 128 times,
The structure was determined from the chemical shift value and integrated value.

<Infrared absorption spectrum (IR) measurement> A Fourier transform infrared spectrophotometer (Nicolet Japan AVATAR 320S FT-IR) for analyzing the structure and conformation of synthetic substances
Was used for the measurement. As a measurement method, for PBLA, a thin film method of forming and measuring a thin film by casting film formation,
For PPMAA, a diffuse reflection method was used in which the powder sample was exposed to light and the reflected light was measured.

<Viscosity Measurement> The viscosity of the synthesized sample was measured to determine the molecular weight. Solvent is dichloroacetic acid
(DCA) was used, and a Ubbelohde type viscosity tube was used as the viscosity tube. Measurement is carried out in a thermostat at 20.0 ° C, and Mark is used to calculate the molecular weight.
-Houwink- formula Sakurada ([η] = KMv ^a) was used. In the calculation, K = 2.78 × 10 ⁻⁵ and a = 0.87.

<Fluorescence spectrum measurement> In order to investigate the stacking state of the side chain pyrenyl group, measurement was carried out using a fluorometer (RF-5300PC manufactured by Shimadzu Corporation). In this measurement, PPMAA was dissolved in dimethylformamide (DMF) so that the pyrene concentration was [Pyr] = 5 × 10 ⁻⁵ mol / l, and the spectrum of this solution was measured. For comparison, 1-pyrenemethylamine was dissolved in dimethylformamide (DMF) so that the concentration was the same, and the spectrum of this solution was also measured.

<Measurement of electrical conductivity> Measurement of resistivity of cast film prepared (Mitsubishi Chemical Hiresta-UP MCP-HT45)
I went. A ring type probe was adopted as the probe shape, and the outer diameter was φ10 for the tip diameter. A sheet made of Teflon (registered trademark) was used for the guard electrode for the measurement of the surface resistivity, and the measurement was performed at 23 ° C. Then, the conductivity was calculated from this surface resistivity. For comparison, the following poly (γ-pyrenemethyl L-glutamate) (PPMLG; α-
Polypeptide) cast films and poly (pyrenemethylmethacrylate) (PPMMA; polymers other than polypeptides) cast films were prepared in the same manner as PPMAA cast films, and the conductivity of these films was also determined.

[0055]

[Chemical 14]

[0056]

[Chemical 15]

[0057] ^<1 H-NMR measurement results showed> (S) -4- ¹ H-NMR measurement results of benzyloxycarbonyl-2-azetidinone in FIG 3, it is also shown the assignment of each peak.

Further, FIG. 4 shows the ¹ H-NMR measurement results of poly (α-benzyl L-aspartate) (PBLA), and the attribution of each peak is also shown.

Further, FIG. 5 shows the ¹ H-NMR measurement results of poly (α-N-pyrenemethyl L-aspartamide) (PPMAA), and the attribution of each peak is also shown. From the result of FIG. 5, it was found that the substitution degree was substantially 100%.

<Infrared absorption spectrum (IR) measurement result> PPMA
The infrared absorption spectra of A and PBLA are shown in FIG. In PPMAA, Amide I band is 1653cm ^-1 , Amide II band is 1540c
Observed at m ^-1 . In PBLA, absorption by C = O of the ester was observed at 1746 cm ^-1 , but in PPMAA, this absorption was hardly observed. Therefore, it was found that the ester bond in the side chain of PBLA was substantially converted into 100% amide bond, and the substitution degree was substantially 100%.

<Viscosity measurement result> Poly (α-benzyl L-
The viscosity average molecular weight of aspartate (PBLA) is about 87.
It was good. The viscosity average molecular weight of poly (α-N-pyrenemethyl L-aspartamide) (PPMAA) is about 3
It was 50,000.

<Results of Fluorescence Spectrum Measurement> It is known that pyrene and similar substances emit fluorescence, and it is well known that the pyrenyl group emits excimer light when the pyrenyl group is packed in addition to the fluorescence emitted by the monomer. ing. Egusa et al. Have proved this from a study of poly (L-pyrenylalanine) (T. Li, R. Giasson,
J. Am. Chem. Soc., 116, 9890, (1994), S. Egusa, M. Sisi.
do, Y.Imanishi, Macromolecules, 18, 882, (198
Five)). According to Egusa et al., Pyrenylalanine does not emit excimer light in the state of a monomer, but when this monomer is polymerized into a polymer and the pyrene ring is aligned, it is reported that it emits excimer light. So PPMA
Regarding A, the stack of pyrenyl groups was examined from the fluorescence measurement. Fig. 7 shows fluorescence of PPMAA and 1-pyrenemethylamine. 1-Pyrenemethylamine was excited at a wavelength of 346 nm and resulted in fluorescence at around 378 nm. In comparison with this spectrum, in the fluorescence spectrum of the same concentration of PPMAA, the pyrenyl group excited at 346 nm showed almost no fluorescence of the monomer alone at 378 nm, and newly showed a broad peak at around 480 nm. This is an excimer peak derived from stacking of the pyrene ring. Stacking was confirmed for PPMAA, and it was found that pyrenyl groups were fixed and arranged along the main chain (see FIG. 2).

<Results of Conductivity Measurement> FIG. 8 shows the relationship between the doping rate and the conductivity of the PPMAA cast film, PPMLG cast film and PPMMA cast film. Here, the doping rate means the ratio of the mol number of iodine to the mol number of the conductive group.

PPMAA extracts π electrons by iodine
As a result, holes are generated inside the pyrene ring and the
Thought to become a conductive polymer with a p-type mechanism in which holes move
To be The conductivity of PPMAA cast film depends on iodine.
As it is doped, it rises sharply in the initial stage,
Dope ratio of 325.8 mol% and maximum of 2.761 × 10 ^−
3Reached S / cm. This is because β-polypeptide is 4 / 1-
It is thought that the conductivity was increased due to the helix structure.
Be done. In addition, poly (α-N-pyrene) with a substitution degree of 50%
Chill L-Aspartamide) (PPMAA) cast film
The conductivity of rum is 2.01 at maximum with a doping rate of 10 mol%.
× 10^-6S / cm, the substitution degree of the present invention is substantially
Very low compared to 100% PPMAA cast film
It was. In addition, PPMMA Cas with a degree of substitution of substantially 100%
The iodine doping rate of the film is from the viewpoint of improving conductivity.
Therefore, 50 to 350 mol% is preferable, and particularly 100 to
It has been found that 350 mol% is preferred.

<Measurement of Electrical Conductivity of Stretched Film> A PBLA cast film was prepared, and the electrical conductivity of this film and the stretched film thereof were measured. Specifically, PBLA 300 mg is dissolved in a mixed solution of CF 5.0 ml, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) 0.3 ml,
Cast film was formed on a Teflon (registered trademark) petri dish to obtain a cast film having a thickness of 400 μm. further,
This film was stretched at a stretching ratio of about 2.5 to give a stretched film.

Then, in the same manner as in the PPMAA cast film, iodine doping was performed and the conductivity was measured. As a result, the electrical conductivity of the unstretched PBLA cast film was 3.0 × 10 ⁻¹³ S / cm at the maximum with a doping rate of 8 mol%. In contrast, the stretched film reached a maximum of 4.0 × 10 ⁻⁵ S / cm at a doping rate of 8 mol%.
This is considered to be because the orientation of the β-polypeptide was improved by the stretching, and the side chains having the conductive group were more regularly arranged on the same plane.

<Synthesis of poly (α-2-thiophenemethyl L-aspartate) (PTMLA)> Next, poly (α-2-thiophenemethyl L-aspartate) (PTMLA) was synthesized. The synthetic scheme is shown in Scheme 7. First, poly (β-L-aspartic acid) (PAA) was synthesized. PB in a sealable sample bottle
LA 0.5 g (2.44 mmol) in DCM Dissolved in 15 ml. After raising the temperature of the system to 50 ° C, add 1.9 ml of trimethylsilyl iodide (Me ₃ SiI).
(13.9 mmol), and seal it to prevent water from entering the system.
The reaction was carried out at 4 ° C for 4 days. During that time, the system changed from a black-purple gel to a black liquid. Add this black liquid to hexane 10
Put in 0 ml to precipitate the polymer, then water 20m in it
Purification was performed while adding 1 to obtain a yellow polymer. Then, the obtained poly (β-L-aspartic acid) (PAA) was vacuum dried. The yield was 67.8%.

[0068]

[Chemical 16]

Then, poly (α-2-thiophenemethyl L-aspartate) (PTMLA) was synthesized from PAA. DMF 15 ml
, PAA 0.30g (2.6mmol), 2-thiophene methanol 0.5
1 g (4.4 mmol) and HOBt 0.39 g (2.6 mmol) were dissolved.
After cooling the system with ice, 0.91 g (2.9 mmol) of DCC was added, and after 2 hours of ice cooling, the mixture was reacted at room temperature for 3 days. DCUr generated by reaction
The ea was removed by filtration and the filtrate was heated to 40 ° C with methanol 40
In 0 ml, poly (α-2-thiophenemethyl L-aspartate) (PTMLA) was precipitated. And this poly (α-2-
Thiophenemethyl L-aspartate) (PTMLA) was vacuum dried. The yield was 60.0%. Then PTMLA 0.0932
g was dissolved in a mixed solution of 4.0 ml of CF and 0.3 ml of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), and the film was slowly cast on a Teflon Petri dish. I went. The thickness of the cast film thus obtained is 47.6.
It was μm.

Iodine doping was performed in the same manner as in the PPMAA cast film, and the conductivity was measured. As a result, PTML
The conductivity of the A cast film sharply increased at the initial stage as iodine was doped, and the doping ratio was 2
The maximum reached 1.54 × 10 ⁻⁶ S / cm at 8.1 mol%. It is considered that this is because β-polypeptide has a 4 / 1-helix structure and thus has high conductivity.

[0071]

INDUSTRIAL APPLICABILITY The β-polypeptide derivative of the present invention has a high conductivity and can be used as an organic conductor in a secondary battery or LE.
It is useful for D, electronic circuit elements (conductive circuit, Schottky type device, pn junction type device), electromagnetic wave (EMI) shield and the like.

[Brief description of drawings]

FIG. 1 shows a conceptual diagram of α-helix.

FIG. 2 shows a conceptual diagram of a 4 / 1-helix.

FIG. 3 shows a ¹ H-NMR chart of (S) -4-benzyloxycarbonyl-2-azetidinone.

FIG. 4 Poly (α-benzyl L-aspartate) (PB
LA) ¹ H-NMR chart is shown.

FIG. 5 shows a ¹ H-NMR chart of poly (α-N-pyrenemethyl L-aspartamide) (PPMAA).

FIG. 6 shows infrared absorption spectra of PPMAA and PBLA.

FIG. 7 shows fluorescence spectra of PPMAA and 1-pyrenemethylamine.

FIG. 8 is a graph showing the relationship between the doping rate and the conductivity of PPMAA cast films, PPMLG cast films, and PPMMA cast films.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Nobuhiro Fukuura             2-8-11 Koyo-cho, Kita-ku, Kobe-shi, Hyogo F-term (reference) 4F071 AA54 AA81 AF37 AH12 AH13                       AH15 BB02 BB07 BC01                 4J001 DA01 DB01 DC11 DD01 DD08                       DD20 EA02 EA03 FA03 GA01                       JA07 JB01 JB39 JC01

Claims (8)

[Claims] 1. A β-polypeptide derivative comprising a β-polypeptide as a main chain, a substituent having a conductive group in the main chain as a side chain, and a degree of substitution of substantially 100%. . 2. A general formula: (In the formula, R represents R = CONHR ₁ , R = COOR ₁ , or R = (CH ₂ ) _n- R _1. However, R ₁ represents a substituent having a conductive group.). A β-polypeptide derivative having substantially 100% of the constituent units. 3. The β according to claim 1 or 2, wherein the conductive group is a condensed polycyclic hydrocarbon group or a thiophene group.
-Polypeptide derivatives. 4. The β-polypeptide derivative according to any one of claims 1 to 3, wherein the conductive group is a pyrenyl group. 5. A molded article comprising the β-polypeptide derivative according to any one of claims 1 to 4. 6. The molded product according to claim 5, which is in the form of a film and is stretched. 7. A general formula: The β-polypeptide derivative having substantially 100% of the structural unit represented by -A method for producing a polypeptide derivative. 8. The method for producing a β-polypeptide derivative according to claim 7, wherein the amine having a conductive group is 1-pyrenemethylamine.